CODEWITHSUNDEEP
c#wpfmvvm-light
Baigoo
Baigoo

Reputation: 41

WPF MVVM Light and modern UI- Passing object to secondary view

I have problem passing object to secondary view in MVVM light WPF. I have main view Model. follow of operation. I am able to wire things up using MVVM light and Modren UI navigation Services. The issue is that i am not able to send object of Main Customer view model to secondary View Model. I want to set data-context of target View from source View Model. I have tried this but does not seem to be working. I prefer no code behind and i have spent a lot of time without any success. 

  public virtual void NavigateTo(string pageKey, object parameter)
    {
        lock (_pagesByKey)
        {
            if (!_pagesByKey.ContainsKey(pageKey))
            {
                throw new ArgumentException(string.Format("No such page: {0}. Did you forget to call NavigationService.Configure?", pageKey), "pageKey");
            }

            var frame = GetDescendantFromName(Application.Current.MainWindow, "ContentFrame") as ModernFrame;

            // Set the frame source, which initiates navigation
            if (frame != null)
            {
                frame.Source = _pagesByKey[pageKey];
               //i Dont know if this should work or not
                frame.DataContext = parameter;

            }
            Parameter = parameter;
            _historic.Add(pageKey);
            CurrentPageKey = pageKey;
        }
    }

any help will be greatly appreciated. I just need to how i can set the datacontext of target View without using code behind. Thanks

Upvotes: 1

Views: 262

Answers (1)

Mikko Viitala
Mikko Viitala

Reputation: 8404

There's multiple possibilities but one that does not create dependencies between your viewmodels is to use pub/sub system in MVVMLight. Basically it goes like this:

When you select some entity from your view and transition to another, viewmodel sends a message that carriers that given entity along. In the other viewmodel you receive the message and set some property accordingly (for editing, adding new entity, etc.)

// mainviewmodel
Messenger.Default.Send(new MyMessage(myObj));

// otherviewmodel
Messenger.Default.Register<MyMessage>(this, message => 
{
    /* do something with message.MyObj */
});

// mymessage
public class MyMessage : MessageBase
{
    ...
    public MyObj MyObj { get; set; }
}

Upvotes: 1

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